<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>菜鸟教程(runoob.com)</title>
</head>
<body>

<p>页面上显示时钟：</p>
<p id="demo"></p>
<button onclick="myStopFunction()">停止</button>
<script>
var myVar=setInterval(function(){myTimer()},1000);
let d;
function myTimer(){
	d=new Date(); //局部
	var t=d.toLocaleTimeString();
	document.getElementById("demo").innerHTML=t;
}
	
function myStopFunction(){
	clearInterval(myVar);
    console.log(d);
}
</script>

</body>
</html>